summaryrefslogtreecommitdiffstats
path: root/doc
diff options
context:
space:
mode:
authorDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 13:37:46 +0000
committerDaniel Baumann <mail@daniel-baumann.ch>2015-11-07 13:37:46 +0000
commite46f7f8dc39b450ee59872552e833d7e00b5a014 (patch)
treea3531971aecdcbcc2a0680091ae23b4df48b6c6b /doc
parentAdding upstream version 0.7. (diff)
downloadlzlib-e46f7f8dc39b450ee59872552e833d7e00b5a014.tar.xz
lzlib-e46f7f8dc39b450ee59872552e833d7e00b5a014.zip
Adding upstream version 0.8.upstream/0.8
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to 'doc')
-rw-r--r--doc/lzlib.info341
-rw-r--r--doc/lzlib.texinfo284
2 files changed, 476 insertions, 149 deletions
diff --git a/doc/lzlib.info b/doc/lzlib.info
index 40862bd..9437d8c 100644
--- a/doc/lzlib.info
+++ b/doc/lzlib.info
@@ -12,23 +12,25 @@ File: lzlib.info, Node: Top, Next: Introduction, Up: (dir)
Lzlib Manual
************
-This manual is for Lzlib (version 0.7, 20 October 2009).
+This manual is for Lzlib (version 0.8, 17 January 2010).
* Menu:
* Introduction:: Purpose and features of Lzlib
* Library Version:: Checking library version
* Buffering:: Sizes of Lzlib's buffers
+* Parameter Limits:: Min / max values for some parameters
* Compression Functions:: Descriptions of the compression functions
* Decompression Functions:: Descriptions of the decompression functions
* Error Codes:: Meaning of codes returned by functions
+* Error Messages:: Error messages corresponding to error codes
* Data Format:: Detailed format of the compressed data
* Examples:: A small tutorial with examples
* Problems:: Reporting bugs
* Concept Index:: Index of concepts
- Copyright (C) 2009 Antonio Diaz Diaz.
+ Copyright (C) 2009, 2010 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission to
copy, distribute and modify it.
@@ -95,7 +97,7 @@ application.
error( "bad library version" );

-File: lzlib.info, Node: Buffering, Next: Compression Functions, Prev: Library Version, Up: Top
+File: lzlib.info, Node: Buffering, Next: Parameter Limits, Prev: Library Version, Up: Top
3 Buffering
***********
@@ -119,24 +121,55 @@ minimum sizes:
`LZ_decompress_write' function. Its size is 64KiB.
* Output decompression buffer. Read from by the `LZ_decompress_read'
- function. Its size is the dictionary size set with the
- `LZ_decompress_open' function or 64KiB, whichever is larger.
+ function. Its size is the dictionary size set in the header of the
+ member currently being decompressed or 64KiB, whichever is larger.

-File: lzlib.info, Node: Compression Functions, Next: Decompression Functions, Prev: Buffering, Up: Top
+File: lzlib.info, Node: Parameter Limits, Next: Compression Functions, Prev: Buffering, Up: Top
-4 Compression Functions
+4 Parameter Limits
+******************
+
+These functions provide minimum and maximum values for some parameters.
+Current values are shown in square brackets.
+
+ -- Function: int LZ_min_dictionary_bits ( void )
+ Returns the base 2 logarithm of the smallest valid dictionary size
+ [12].
+
+ -- Function: int LZ_min_dictionary_size ( void )
+ Returns the smallest valid dictionary size [4KiB].
+
+ -- Function: int LZ_max_dictionary_bits ( void )
+ Returns the base 2 logarithm of the largest valid dictionary size
+ [29].
+
+ -- Function: int LZ_max_dictionary_size ( void )
+ Returns the largest valid dictionary size [512MiB].
+
+ -- Function: int LZ_min_match_len_limit ( void )
+ Returns the smallest valid match length limit [5].
+
+ -- Function: int LZ_max_match_len_limit ( void )
+ Returns the largest valid match length limit [273].
+
+
+File: lzlib.info, Node: Compression Functions, Next: Decompression Functions, Prev: Parameter Limits, Up: Top
+
+5 Compression Functions
***********************
These are the functions used to compress data. In case of error, all of
them return -1, except `LZ_compress_open' whose return value must be
verified by calling `LZ_compress_errno' before using it.
- -- Function: void * LZ_compress_open ( const int DICTIONARY_SIZE,
- const int MATCH_LEN_LIMIT, const long long MEMBER_SIZE )
+ -- Function: struct LZ_Encoder * LZ_compress_open ( const int
+ DICTIONARY_SIZE, const int MATCH_LEN_LIMIT, const long long
+ MEMBER_SIZE )
Initializes the internal stream state for compression and returns a
pointer that can only be used as the ENCODER argument for the
- other LZ_compress functions.
+ other LZ_compress functions, or a null pointer if the encoder
+ could not be allocated.
The returned pointer must be verified by calling
`LZ_compress_errno' before using it. If `LZ_compress_errno' does
@@ -158,31 +191,37 @@ verified by calling `LZ_compress_errno' before using it.
stream, give MEMBER_SIZE a value larger than the amount of data to
be produced, for example LLONG_MAX.
- -- Function: int LZ_compress_restart_member ( void * const ENCODER,
- const long long MEMBER_SIZE )
- Use this function to start a new member, in a multimember data
- stream. Call this function only after
- `LZ_compress_member_finished' indicates that the current member
- has been fully read (with the `LZ_compress_read' function).
-
- -- Function: int LZ_compress_close ( void * const ENCODER )
+ -- Function: int LZ_compress_close ( struct LZ_Encoder * const ENCODER
+ )
Frees all dynamically allocated data structures for this stream.
This function discards any unprocessed input and does not flush
any pending output. After a call to `LZ_compress_close', ENCODER
can no more be used as an argument to any LZ_compress function.
- -- Function: int LZ_compress_finish ( void * const ENCODER )
- Use this function to tell `lzlib' that all the data for this stream
+ -- Function: int LZ_compress_finish ( struct LZ_Encoder * const
+ ENCODER )
+ Use this function to tell `lzlib' that all the data for this member
has already been written (with the `LZ_compress_write' function).
+ After all the produced compressed data has been read with
+ `LZ_compress_read' and `LZ_compress_member_finished' returns 1, a
+ new member can be started with `LZ_compress_restart_member'.
+
+ -- Function: int LZ_compress_restart_member ( struct LZ_Encoder *
+ const ENCODER, const long long MEMBER_SIZE )
+ Use this function to start a new member, in a multimember data
+ stream. Call this function only after
+ `LZ_compress_member_finished' indicates that the current member
+ has been fully read (with the `LZ_compress_read' function).
- -- Function: int LZ_compress_sync_flush ( void * const ENCODER )
+ -- Function: int LZ_compress_sync_flush ( struct LZ_Encoder * const
+ ENCODER )
Use this function to make available to `LZ_compress_read' all the
data already written with the `LZ_compress_write' function.
Repeated use of `LZ_compress_sync_flush' may degrade compression
ratio, so use it only when needed.
- -- Function: int LZ_compress_read ( void * const ENCODER, uint8_t *
- const BUFFER, const int SIZE )
+ -- Function: int LZ_compress_read ( struct LZ_Encoder * const ENCODER,
+ uint8_t * const BUFFER, const int SIZE )
The `LZ_compress_read' function reads up to SIZE bytes from the
stream pointed to by ENCODER, storing the results in BUFFER.
@@ -192,8 +231,8 @@ verified by calling `LZ_compress_errno' before using it.
`LZ_compress_write' function. Note that reading less than SIZE
bytes is not an error.
- -- Function: int LZ_compress_write ( void * const ENCODER, uint8_t *
- const BUFFER, const int SIZE )
+ -- Function: int LZ_compress_write ( struct LZ_Encoder * const
+ ENCODER, uint8_t * const BUFFER, const int SIZE )
The `LZ_compress_write' function writes up to SIZE bytes from
BUFFER to the stream pointed to by ENCODER.
@@ -201,7 +240,8 @@ verified by calling `LZ_compress_errno' before using it.
might be less than SIZE. Note that writing less than SIZE bytes is
not an error.
- -- Function: int LZ_compress_write_size ( void * const ENCODER )
+ -- Function: int LZ_compress_write_size ( struct LZ_Encoder * const
+ ENCODER )
The `LZ_compress_write_size' function returns the maximum number of
bytes that can be inmediately written through the
`LZ_compress_write' function.
@@ -209,69 +249,94 @@ verified by calling `LZ_compress_errno' before using it.
It is guaranteed that an inmediate call to `LZ_compress_write' will
accept a SIZE up to the returned number of bytes.
- -- Function: enum LZ_errno LZ_compress_errno ( void * const ENCODER )
+ -- Function: enum LZ_Errno LZ_compress_errno ( struct LZ_Encoder *
+ const ENCODER )
Returns the current error code for ENCODER (*note Error Codes::)
- -- Function: int LZ_compress_finished ( void * const ENCODER )
+ -- Function: int LZ_compress_finished ( struct LZ_Encoder * const
+ ENCODER )
Returns 1 if all the data has been read and `LZ_compress_close' can
be safely called. Otherwise it returns 0.
- -- Function: int LZ_compress_member_finished ( void * const ENCODER )
+ -- Function: int LZ_compress_member_finished ( struct LZ_Encoder *
+ const ENCODER )
Returns 1 if the current member, in a multimember data stream, has
been fully read and `LZ_compress_restart_member' can be safely
called. Otherwise it returns 0.
- -- Function: long long LZ_compress_data_position ( void * const
- ENCODER )
+ -- Function: long long LZ_compress_data_position ( struct LZ_Encoder *
+ const ENCODER )
Returns the number of input bytes already compressed in the current
member.
- -- Function: long long LZ_compress_member_position ( void * const
- ENCODER )
+ -- Function: long long LZ_compress_member_position ( struct LZ_Encoder
+ * const ENCODER )
Returns the number of compressed bytes already produced, but
perhaps not yet read, in the current member.
- -- Function: long long LZ_compress_total_in_size ( void * const
- ENCODER )
+ -- Function: long long LZ_compress_total_in_size ( struct LZ_Encoder *
+ const ENCODER )
Returns the total number of input bytes already compressed.
- -- Function: long long LZ_compress_total_out_size ( void * const
- ENCODER )
+ -- Function: long long LZ_compress_total_out_size ( struct LZ_Encoder
+ * const ENCODER )
Returns the total number of compressed bytes already produced, but
perhaps not yet read.

File: lzlib.info, Node: Decompression Functions, Next: Error Codes, Prev: Compression Functions, Up: Top
-5 Decompression Functions
+6 Decompression Functions
*************************
These are the functions used to decompress data. In case of error, all
of them return -1, except `LZ_decompress_open' whose return value must
be verified by calling `LZ_decompress_errno' before using it.
- -- Function: void * LZ_decompress_open ( void )
+ -- Function: struct LZ_Decoder * LZ_decompress_open ( void )
Initializes the internal stream state for decompression and
returns a pointer that can only be used as the DECODER argument
- for the other LZ_decompress functions.
+ for the other LZ_decompress functions, or a null pointer if the
+ decoder could not be allocated.
The returned pointer must be verified by calling
`LZ_decompress_errno' before using it. If `LZ_decompress_errno'
does not return `LZ_ok', the returned pointer must not be used and
should be freed with `LZ_decompress_close' to avoid memory leaks.
- -- Function: int LZ_decompress_close ( void * const DECODER )
+ -- Function: int LZ_decompress_close ( struct LZ_Decoder * const
+ DECODER )
Frees all dynamically allocated data structures for this stream.
This function discards any unprocessed input and does not flush
any pending output. After a call to `LZ_decompress_close', DECODER
can no more be used as an argument to any LZ_decompress function.
- -- Function: int LZ_decompress_finish ( void * const DECODER )
+ -- Function: int LZ_decompress_finish ( struct LZ_Decoder * const
+ DECODER )
Use this function to tell `lzlib' that all the data for this stream
has already been written (with the `LZ_decompress_write' function).
- -- Function: int LZ_decompress_read ( void * const DECODER, uint8_t *
- const BUFFER, const int SIZE )
+ -- Function: int LZ_decompress_reset ( struct LZ_Decoder * const
+ DECODER )
+ Resets the internal state of DECODER as it was just after opening
+ it with the `LZ_decompress_open' function. Data stored in the
+ internal buffers is discarded. Position counters are set to 0.
+
+ -- Function: int LZ_decompress_sync_to_member ( struct LZ_Decoder *
+ const DECODER )
+ Resets the error state of DECODER and enters a search state that
+ lasts until a new member header (or the end of the stream) is
+ found. After a successful call to `LZ_decompress_sync_to_member',
+ data written with `LZ_decompress_write' will be consumed and
+ `LZ_decompress_read' will return 0 until a header is found.
+
+ This function is useful to discard any data preceding the first
+ member, or to discard the rest of the current member, for example
+ in case of a data error. If the decoder is already at the
+ beginning of a member, this function does nothing.
+
+ -- Function: int LZ_decompress_read ( struct LZ_Decoder * const
+ DECODER, uint8_t * const BUFFER, const int SIZE )
The `LZ_decompress_read' function reads up to SIZE bytes from the
stream pointed to by DECODER, storing the results in BUFFER.
@@ -281,8 +346,8 @@ be verified by calling `LZ_decompress_errno' before using it.
`LZ_decompress_write' function. Note that reading less than SIZE
bytes is not an error.
- -- Function: int LZ_decompress_write ( void * const DECODER, uint8_t *
- const BUFFER, const int SIZE )
+ -- Function: int LZ_decompress_write ( struct LZ_Decoder * const
+ DECODER, uint8_t * const BUFFER, const int SIZE )
The `LZ_decompress_write' function writes up to SIZE bytes from
BUFFER to the stream pointed to by DECODER.
@@ -290,36 +355,47 @@ be verified by calling `LZ_decompress_errno' before using it.
might be less than SIZE. Note that writing less than SIZE bytes is
not an error.
- -- Function: enum LZ_errno LZ_decompress_errno ( void * const DECODER )
+ -- Function: int LZ_decompress_write_size ( struct LZ_Decoder * const
+ DECODER )
+ The `LZ_decompress_write_size' function returns the maximum number
+ of bytes that can be inmediately written through the
+ `LZ_decompress_write' function.
+
+ It is guaranteed that an inmediate call to `LZ_decompress_write'
+ will accept a SIZE up to the returned number of bytes.
+
+ -- Function: enum LZ_Errno LZ_decompress_errno ( struct LZ_Decoder *
+ const DECODER )
Returns the current error code for DECODER (*note Error Codes::)
- -- Function: int LZ_decompress_finished ( void * const DECODER )
+ -- Function: int LZ_decompress_finished ( struct LZ_Decoder * const
+ DECODER )
Returns 1 if all the data has been read and `LZ_decompress_close'
can be safely called. Otherwise it returns 0.
- -- Function: long long LZ_decompress_data_position ( void * const
- DECODER )
+ -- Function: long long LZ_decompress_data_position ( struct LZ_Decoder
+ * const DECODER )
Returns the number of decompressed bytes already produced, but
perhaps not yet read, in the current member.
- -- Function: long long LZ_decompress_member_position ( void * const
- DECODER )
+ -- Function: long long LZ_decompress_member_position ( struct
+ LZ_Decoder * const DECODER )
Returns the number of input bytes already decompressed in the
current member.
- -- Function: long long LZ_decompress_total_in_size ( void * const
- DECODER )
+ -- Function: long long LZ_decompress_total_in_size ( struct LZ_Decoder
+ * const DECODER )
Returns the total number of input bytes already decompressed.
- -- Function: long long LZ_decompress_total_out_size ( void * const
- DECODER )
+ -- Function: long long LZ_decompress_total_out_size ( struct
+ LZ_Decoder * const DECODER )
Returns the total number of decompressed bytes already produced,
but perhaps not yet read.

-File: lzlib.info, Node: Error Codes, Next: Data Format, Prev: Decompression Functions, Up: Top
+File: lzlib.info, Node: Error Codes, Next: Error Messages, Prev: Decompression Functions, Up: Top
-6 Error Codes
+7 Error Codes
*************
Most library functions return -1 to indicate that they have failed. But
@@ -336,42 +412,58 @@ whether a call failed. If the call failed, then you can examine
The error codes are defined in the header file `lzlib.h'.
- -- Constant: enum LZ_errno LZ_ok
+ -- Constant: enum LZ_Errno LZ_ok
The value of this constant is 0 and is used to indicate that there
is no error.
- -- Constant: enum LZ_errno LZ_bad_argument
+ -- Constant: enum LZ_Errno LZ_bad_argument
At least one of the arguments passed to the library function was
invalid.
- -- Constant: enum LZ_errno LZ_mem_error
+ -- Constant: enum LZ_Errno LZ_mem_error
No memory available. The system cannot allocate more virtual memory
because its capacity is full.
- -- Constant: enum LZ_errno LZ_sequence_error
+ -- Constant: enum LZ_Errno LZ_sequence_error
A library function was called in the wrong order. For example
`LZ_compress_restart_member' was called before
`LZ_compress_member_finished' indicates that the current member is
finished.
- -- Constant: enum LZ_errno LZ_header_error
+ -- Constant: enum LZ_Errno LZ_header_error
Reading of member header failed. If this happens at the end of the
data stream it may indicate trailing garbage.
- -- Constant: enum LZ_errno LZ_unexpected_eof
+ -- Constant: enum LZ_Errno LZ_unexpected_eof
The end of the data stream was reached in the middle of a member.
- -- Constant: enum LZ_errno LZ_data_error
+ -- Constant: enum LZ_Errno LZ_data_error
The data stream is corrupt.
- -- Constant: enum LZ_errno LZ_library_error
+ -- Constant: enum LZ_Errno LZ_library_error
A bug was detected in the library. Please, report it (*note
Problems::).

-File: lzlib.info, Node: Data Format, Next: Examples, Prev: Error Codes, Up: Top
+File: lzlib.info, Node: Error Messages, Next: Data Format, Prev: Error Codes, Up: Top
+
+8 Error Messages
+****************
+
+ -- Function: const char * LZ_strerror ( const enum LZ_Errno LZ_ERRNO )
+ Returns the standard error message for a given error code. The
+ messages are fairly short; there are no multi-line messages or
+ embedded newlines. This function makes it easy for your program
+ to report informative error messages about the failure of a
+ library call.
+
+ The value of LZ_ERRNO normally comes from a call to
+ `LZ_(de)compress_errno'.
+
+
+File: lzlib.info, Node: Data Format, Next: Examples, Prev: Error Messages, Up: Top
-7 Data Format
+9 Data Format
*************
In the diagram below, a box like this:
@@ -433,8 +525,8 @@ with no additional information before, between, or after them.

File: lzlib.info, Node: Examples, Next: Problems, Prev: Data Format, Up: Top
-8 A small tutorial with examples
-********************************
+10 A small tutorial with examples
+*********************************
This chaper shows the order in which the library functions should be
called depending on what kind of data stream you want to compress or
@@ -453,7 +545,18 @@ Example 1: Normal compression (MEMBER_SIZE > total output).
8) LZ_compress_close
-Example 2: Decompression.
+Example 2: Normal compression using LZ_compress_write_size.
+
+ 1) LZ_compress_open
+ 2) go to step 5 if LZ_compress_write_size returns 0
+ 3) LZ_compress_write
+ 4) if no more data to write, call LZ_compress_finish
+ 5) LZ_compress_read
+ 6) go back to step 2 until LZ_compress_finished returns 1
+ 7) LZ_compress_close
+
+
+Example 3: Decompression.
1) LZ_decompress_open
2) LZ_decompress_write
@@ -465,24 +568,76 @@ Example 2: Decompression.
8) LZ_decompress_close
-Example 3: Multimember compression (MEMBER_SIZE < total output).
+Example 4: Decompression using LZ_decompress_write_size.
+
+ 1) LZ_decompress_open
+ 2) go to step 5 if LZ_decompress_write_size returns 0
+ 3) LZ_decompress_write
+ 4) if no more data to write, call LZ_decompress_finish
+ 5) LZ_decompress_read
+ 6) go back to step 2 until LZ_decompress_finished returns 1
+ 7) LZ_decompress_close
+
+
+Example 5: Multimember compression (MEMBER_SIZE < total output).
+
+ 1) LZ_compress_open
+ 2) go to step 5 if LZ_compress_write_size returns 0
+ 3) LZ_compress_write
+ 4) if no more data to write, call LZ_compress_finish
+ 5) LZ_compress_read
+ 6) go back to step 2 until LZ_compress_member_finished returns 1
+ 7) go to step 10 if LZ_compress_finished() returns 1
+ 8) LZ_compress_restart_member
+ 9) go back to step 2
+ 10) LZ_compress_close
+
+
+Example 6: Multimember compression (user-restarted members).
1) LZ_compress_open
2) LZ_compress_write
3) LZ_compress_read
- 4) go back to step 2 until LZ_compress_member_finished returns 1
- 5) LZ_compress_restart_member
- 6) go back to step 2 until all input data has been written
- 7) LZ_compress_finish
- 8) LZ_compress_read
- 9) go back to step 8 until LZ_compress_finished returns 1
- 10) LZ_compress_close
+ 4) go back to step 2 until member termination is desired
+ 5) LZ_compress_finish
+ 6) LZ_compress_read
+ 7) go back to step 6 until LZ_compress_member_finished returns 1
+ 8) verify that LZ_compress_finished returns 1
+ 9) go to step 12 if all input data has been written
+ 10) LZ_compress_restart_member
+ 11) go back to step 2
+ 12) LZ_compress_close
+
+
+Example 7: Decompression with automatic removal of leading garbage.
+
+ 1) LZ_decompress_open
+ 2) LZ_decompress_sync_to_member
+ 3) go to step 6 if LZ_decompress_write_size returns 0
+ 4) LZ_decompress_write
+ 5) if no more data to write, call LZ_decompress_finish
+ 6) LZ_decompress_read
+ 7) go back to step 3 until LZ_decompress_finished returns 1
+ 8) LZ_decompress_close
+
+
+Example 8: Streamed decompression with automatic resynchronization to
+next member in case of data error.
+
+ 1) LZ_decompress_open
+ 2) go to step 5 if LZ_decompress_write_size returns 0
+ 3) LZ_decompress_write
+ 4) if no more data to write, call LZ_decompress_finish
+ 5) if LZ_decompress_read produces LZ_header_error or LZ_data_error,
+ call LZ_decompress_sync_to_member
+ 6) go back to step 2 until LZ_decompress_finished returns 1
+ 7) LZ_decompress_close

File: lzlib.info, Node: Problems, Next: Concept Index, Prev: Examples, Up: Top
-9 Reporting Bugs
-****************
+11 Reporting Bugs
+*****************
There are probably bugs in Lzlib. There are certainly errors and
omissions in this manual. If you report them, they will get fixed. If
@@ -510,24 +665,28 @@ Concept Index
* decompression functions: Decompression Functions.
(line 6)
* error codes: Error Codes. (line 6)
+* error messages: Error Messages. (line 6)
* examples: Examples. (line 6)
* getting help: Problems. (line 6)
* introduction: Introduction. (line 6)
* library version: Library Version. (line 6)
+* parameter limits: Parameter Limits. (line 6)

Tag Table:
Node: Top219
-Node: Introduction1028
-Node: Library Version2803
-Node: Buffering3448
-Node: Compression Functions4555
-Node: Decompression Functions10057
-Node: Error Codes13495
-Node: Data Format15431
-Node: Examples17398
-Node: Problems18832
-Node: Concept Index19402
+Node: Introduction1157
+Node: Library Version2932
+Node: Buffering3577
+Node: Parameter Limits4697
+Node: Compression Functions5654
+Node: Decompression Functions11700
+Node: Error Codes16762
+Node: Error Messages18701
+Node: Data Format19280
+Node: Examples21250
+Node: Problems24826
+Node: Concept Index25398

End Tag Table
diff --git a/doc/lzlib.texinfo b/doc/lzlib.texinfo
index a824739..ae22e44 100644
--- a/doc/lzlib.texinfo
+++ b/doc/lzlib.texinfo
@@ -5,8 +5,8 @@
@finalout
@c %**end of header
-@set UPDATED 20 October 2009
-@set VERSION 0.7
+@set UPDATED 17 January 2010
+@set VERSION 0.8
@dircategory Data Compression
@direntry
@@ -35,9 +35,11 @@ This manual is for Lzlib (version @value{VERSION}, @value{UPDATED}).
* Introduction:: Purpose and features of Lzlib
* Library Version:: Checking library version
* Buffering:: Sizes of Lzlib's buffers
+* Parameter Limits:: Min / max values for some parameters
* Compression Functions:: Descriptions of the compression functions
* Decompression Functions:: Descriptions of the decompression functions
* Error Codes:: Meaning of codes returned by functions
+* Error Messages:: Error messages corresponding to error codes
* Data Format:: Detailed format of the compressed data
* Examples:: A small tutorial with examples
* Problems:: Reporting bugs
@@ -45,7 +47,7 @@ This manual is for Lzlib (version @value{VERSION}, @value{UPDATED}).
@end menu
@sp 1
-Copyright @copyright{} 2009 Antonio Diaz Diaz.
+Copyright @copyright{} 2009, 2010 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission
to copy, distribute and modify it.
@@ -139,11 +141,43 @@ is larger.
@item Output decompression buffer. Read from by the
@samp{LZ_decompress_read} function. Its size is the dictionary size set
-with the @samp{LZ_decompress_open} function or 64KiB, whichever is
-larger.
+in the header of the member currently being decompressed or 64KiB,
+whichever is larger.
@end itemize
+@node Parameter Limits
+@chapter Parameter Limits
+@cindex parameter limits
+
+These functions provide minimum and maximum values for some parameters.
+Current values are shown in square brackets.
+
+@deftypefun int LZ_min_dictionary_bits ( void )
+Returns the base 2 logarithm of the smallest valid dictionary size [12].
+@end deftypefun
+
+@deftypefun int LZ_min_dictionary_size ( void )
+Returns the smallest valid dictionary size [4KiB].
+@end deftypefun
+
+@deftypefun int LZ_max_dictionary_bits ( void )
+Returns the base 2 logarithm of the largest valid dictionary size [29].
+@end deftypefun
+
+@deftypefun int LZ_max_dictionary_size ( void )
+Returns the largest valid dictionary size [512MiB].
+@end deftypefun
+
+@deftypefun int LZ_min_match_len_limit ( void )
+Returns the smallest valid match length limit [5].
+@end deftypefun
+
+@deftypefun int LZ_max_match_len_limit ( void )
+Returns the largest valid match length limit [273].
+@end deftypefun
+
+
@node Compression Functions
@chapter Compression Functions
@cindex compression functions
@@ -153,10 +187,11 @@ them return -1, except @samp{LZ_compress_open} whose return value must
be verified by calling @samp{LZ_compress_errno} before using it.
-@deftypefun {void *} LZ_compress_open ( const int @var{dictionary_size}, const int @var{match_len_limit}, const long long @var{member_size} )
+@deftypefun {struct LZ_Encoder *} LZ_compress_open ( const int @var{dictionary_size}, const int @var{match_len_limit}, const long long @var{member_size} )
Initializes the internal stream state for compression and returns a
pointer that can only be used as the @var{encoder} argument for the
-other LZ_compress functions.
+other LZ_compress functions, or a null pointer if the encoder could not
+be allocated.
The returned pointer must be verified by calling
@samp{LZ_compress_errno} before using it. If @samp{LZ_compress_errno}
@@ -180,15 +215,7 @@ for example LLONG_MAX.
@end deftypefun
-@deftypefun int LZ_compress_restart_member ( void * const @var{encoder}, const long long @var{member_size} )
-Use this function to start a new member, in a multimember data stream.
-Call this function only after @samp{LZ_compress_member_finished}
-indicates that the current member has been fully read (with the
-@samp{LZ_compress_read} function).
-@end deftypefun
-
-
-@deftypefun int LZ_compress_close ( void * const @var{encoder} )
+@deftypefun int LZ_compress_close ( struct LZ_Encoder * const @var{encoder} )
Frees all dynamically allocated data structures for this stream. This
function discards any unprocessed input and does not flush any pending
output. After a call to @samp{LZ_compress_close}, @var{encoder} can no
@@ -196,13 +223,24 @@ more be used as an argument to any LZ_compress function.
@end deftypefun
-@deftypefun int LZ_compress_finish ( void * const @var{encoder} )
-Use this function to tell @samp{lzlib} that all the data for this stream
+@deftypefun int LZ_compress_finish ( struct LZ_Encoder * const @var{encoder} )
+Use this function to tell @samp{lzlib} that all the data for this member
has already been written (with the @samp{LZ_compress_write} function).
+After all the produced compressed data has been read with
+@samp{LZ_compress_read} and @samp{LZ_compress_member_finished} returns
+1, a new member can be started with @samp{LZ_compress_restart_member}.
@end deftypefun
-@deftypefun int LZ_compress_sync_flush ( void * const @var{encoder} )
+@deftypefun int LZ_compress_restart_member ( struct LZ_Encoder * const @var{encoder}, const long long @var{member_size} )
+Use this function to start a new member, in a multimember data stream.
+Call this function only after @samp{LZ_compress_member_finished}
+indicates that the current member has been fully read (with the
+@samp{LZ_compress_read} function).
+@end deftypefun
+
+
+@deftypefun int LZ_compress_sync_flush ( struct LZ_Encoder * const @var{encoder} )
Use this function to make available to @samp{LZ_compress_read} all the
data already written with the @samp{LZ_compress_write} function.
Repeated use of @samp{LZ_compress_sync_flush} may degrade compression
@@ -210,7 +248,7 @@ ratio, so use it only when needed.
@end deftypefun
-@deftypefun int LZ_compress_read ( void * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} )
+@deftypefun int LZ_compress_read ( struct LZ_Encoder * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} )
The @samp{LZ_compress_read} function reads up to @var{size} bytes from
the stream pointed to by @var{encoder}, storing the results in
@var{buffer}.
@@ -223,7 +261,7 @@ in the stream or if more bytes have to be yet written with the
@end deftypefun
-@deftypefun int LZ_compress_write ( void * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} )
+@deftypefun int LZ_compress_write ( struct LZ_Encoder * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} )
The @samp{LZ_compress_write} function writes up to @var{size} bytes from
@var{buffer} to the stream pointed to by @var{encoder}.
@@ -233,7 +271,7 @@ not an error.
@end deftypefun
-@deftypefun int LZ_compress_write_size ( void * const @var{encoder} )
+@deftypefun int LZ_compress_write_size ( struct LZ_Encoder * const @var{encoder} )
The @samp{LZ_compress_write_size} function returns the maximum number of
bytes that can be inmediately written through the @samp{LZ_compress_write}
function.
@@ -243,42 +281,42 @@ accept a @var{size} up to the returned number of bytes.
@end deftypefun
-@deftypefun {enum LZ_errno} LZ_compress_errno ( void * const @var{encoder} )
+@deftypefun {enum LZ_Errno} LZ_compress_errno ( struct LZ_Encoder * const @var{encoder} )
Returns the current error code for @var{encoder} (@pxref{Error Codes})
@end deftypefun
-@deftypefun int LZ_compress_finished ( void * const @var{encoder} )
+@deftypefun int LZ_compress_finished ( struct LZ_Encoder * const @var{encoder} )
Returns 1 if all the data has been read and @samp{LZ_compress_close} can
be safely called. Otherwise it returns 0.
@end deftypefun
-@deftypefun int LZ_compress_member_finished ( void * const @var{encoder} )
+@deftypefun int LZ_compress_member_finished ( struct LZ_Encoder * const @var{encoder} )
Returns 1 if the current member, in a multimember data stream, has been
fully read and @samp{LZ_compress_restart_member} can be safely called.
Otherwise it returns 0.
@end deftypefun
-@deftypefun {long long} LZ_compress_data_position ( void * const @var{encoder} )
+@deftypefun {long long} LZ_compress_data_position ( struct LZ_Encoder * const @var{encoder} )
Returns the number of input bytes already compressed in the current
member.
@end deftypefun
-@deftypefun {long long} LZ_compress_member_position ( void * const @var{encoder} )
+@deftypefun {long long} LZ_compress_member_position ( struct LZ_Encoder * const @var{encoder} )
Returns the number of compressed bytes already produced, but perhaps not
yet read, in the current member.
@end deftypefun
-@deftypefun {long long} LZ_compress_total_in_size ( void * const @var{encoder} )
+@deftypefun {long long} LZ_compress_total_in_size ( struct LZ_Encoder * const @var{encoder} )
Returns the total number of input bytes already compressed.
@end deftypefun
-@deftypefun {long long} LZ_compress_total_out_size ( void * const @var{encoder} )
+@deftypefun {long long} LZ_compress_total_out_size ( struct LZ_Encoder * const @var{encoder} )
Returns the total number of compressed bytes already produced, but
perhaps not yet read.
@end deftypefun
@@ -293,10 +331,11 @@ of them return -1, except @samp{LZ_decompress_open} whose return value
must be verified by calling @samp{LZ_decompress_errno} before using it.
-@deftypefun {void *} LZ_decompress_open ( void )
+@deftypefun {struct LZ_Decoder *} LZ_decompress_open ( void )
Initializes the internal stream state for decompression and returns a
pointer that can only be used as the @var{decoder} argument for the
-other LZ_decompress functions.
+other LZ_decompress functions, or a null pointer if the decoder could
+not be allocated.
The returned pointer must be verified by calling
@samp{LZ_decompress_errno} before using it. If
@@ -306,7 +345,7 @@ pointer must not be used and should be freed with
@end deftypefun
-@deftypefun int LZ_decompress_close ( void * const @var{decoder} )
+@deftypefun int LZ_decompress_close ( struct LZ_Decoder * const @var{decoder} )
Frees all dynamically allocated data structures for this stream. This
function discards any unprocessed input and does not flush any pending
output. After a call to @samp{LZ_decompress_close}, @var{decoder} can no
@@ -314,13 +353,34 @@ more be used as an argument to any LZ_decompress function.
@end deftypefun
-@deftypefun int LZ_decompress_finish ( void * const @var{decoder} )
+@deftypefun int LZ_decompress_finish ( struct LZ_Decoder * const @var{decoder} )
Use this function to tell @samp{lzlib} that all the data for this stream
has already been written (with the @samp{LZ_decompress_write} function).
@end deftypefun
-@deftypefun int LZ_decompress_read ( void * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} )
+@deftypefun int LZ_decompress_reset ( struct LZ_Decoder * const @var{decoder} )
+Resets the internal state of @var{decoder} as it was just after opening
+it with the @samp{LZ_decompress_open} function. Data stored in the
+internal buffers is discarded. Position counters are set to 0.
+@end deftypefun
+
+
+@deftypefun int LZ_decompress_sync_to_member ( struct LZ_Decoder * const @var{decoder} )
+Resets the error state of @var{decoder} and enters a search state that
+lasts until a new member header (or the end of the stream) is found.
+After a successful call to @samp{LZ_decompress_sync_to_member}, data
+written with @samp{LZ_decompress_write} will be consumed and
+@samp{LZ_decompress_read} will return 0 until a header is found.
+
+This function is useful to discard any data preceding the first member,
+or to discard the rest of the current member, for example in case of a
+data error. If the decoder is already at the beginning of a member, this
+function does nothing.
+@end deftypefun
+
+
+@deftypefun int LZ_decompress_read ( struct LZ_Decoder * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} )
The @samp{LZ_decompress_read} function reads up to @var{size} bytes from
the stream pointed to by @var{decoder}, storing the results in
@var{buffer}.
@@ -333,7 +393,7 @@ in the stream or if more bytes have to be yet written with the
@end deftypefun
-@deftypefun int LZ_decompress_write ( void * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} )
+@deftypefun int LZ_decompress_write ( struct LZ_Decoder * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} )
The @samp{LZ_decompress_write} function writes up to @var{size} bytes from
@var{buffer} to the stream pointed to by @var{decoder}.
@@ -343,35 +403,45 @@ not an error.
@end deftypefun
-@deftypefun {enum LZ_errno} LZ_decompress_errno ( void * const @var{decoder} )
+@deftypefun int LZ_decompress_write_size ( struct LZ_Decoder * const @var{decoder} )
+The @samp{LZ_decompress_write_size} function returns the maximum number
+of bytes that can be inmediately written through the
+@samp{LZ_decompress_write} function.
+
+It is guaranteed that an inmediate call to @samp{LZ_decompress_write}
+will accept a @var{size} up to the returned number of bytes.
+@end deftypefun
+
+
+@deftypefun {enum LZ_Errno} LZ_decompress_errno ( struct LZ_Decoder * const @var{decoder} )
Returns the current error code for @var{decoder} (@pxref{Error Codes})
@end deftypefun
-@deftypefun int LZ_decompress_finished ( void * const @var{decoder} )
+@deftypefun int LZ_decompress_finished ( struct LZ_Decoder * const @var{decoder} )
Returns 1 if all the data has been read and @samp{LZ_decompress_close}
can be safely called. Otherwise it returns 0.
@end deftypefun
-@deftypefun {long long} LZ_decompress_data_position ( void * const @var{decoder} )
+@deftypefun {long long} LZ_decompress_data_position ( struct LZ_Decoder * const @var{decoder} )
Returns the number of decompressed bytes already produced, but perhaps
not yet read, in the current member.
@end deftypefun
-@deftypefun {long long} LZ_decompress_member_position ( void * const @var{decoder} )
+@deftypefun {long long} LZ_decompress_member_position ( struct LZ_Decoder * const @var{decoder} )
Returns the number of input bytes already decompressed in the current
member.
@end deftypefun
-@deftypefun {long long} LZ_decompress_total_in_size ( void * const @var{decoder} )
+@deftypefun {long long} LZ_decompress_total_in_size ( struct LZ_Decoder * const @var{decoder} )
Returns the total number of input bytes already decompressed.
@end deftypefun
-@deftypefun {long long} LZ_decompress_total_out_size ( void * const @var{decoder} )
+@deftypefun {long long} LZ_decompress_total_out_size ( struct LZ_Decoder * const @var{decoder} )
Returns the total number of decompressed bytes already produced, but
perhaps not yet read.
@end deftypefun
@@ -395,46 +465,61 @@ examine @samp{LZ_(de)compress_errno}.
The error codes are defined in the header file @samp{lzlib.h}.
-@deftypevr Constant {enum LZ_errno} LZ_ok
+@deftypevr Constant {enum LZ_Errno} LZ_ok
The value of this constant is 0 and is used to indicate that there is no
error.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_bad_argument
+@deftypevr Constant {enum LZ_Errno} LZ_bad_argument
At least one of the arguments passed to the library function was
invalid.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_mem_error
+@deftypevr Constant {enum LZ_Errno} LZ_mem_error
No memory available. The system cannot allocate more virtual memory
because its capacity is full.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_sequence_error
+@deftypevr Constant {enum LZ_Errno} LZ_sequence_error
A library function was called in the wrong order. For example
@samp{LZ_compress_restart_member} was called before
@samp{LZ_compress_member_finished} indicates that the current member is
finished.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_header_error
+@deftypevr Constant {enum LZ_Errno} LZ_header_error
Reading of member header failed. If this happens at the end of the data
stream it may indicate trailing garbage.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_unexpected_eof
+@deftypevr Constant {enum LZ_Errno} LZ_unexpected_eof
The end of the data stream was reached in the middle of a member.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_data_error
+@deftypevr Constant {enum LZ_Errno} LZ_data_error
The data stream is corrupt.
@end deftypevr
-@deftypevr Constant {enum LZ_errno} LZ_library_error
+@deftypevr Constant {enum LZ_Errno} LZ_library_error
A bug was detected in the library. Please, report it (@pxref{Problems}).
@end deftypevr
+@node Error Messages
+@chapter Error Messages
+@cindex error messages
+
+@deftypefun {const char *} LZ_strerror ( const enum LZ_Errno @var{lz_errno} )
+Returns the standard error message for a given error code. The messages
+are fairly short; there are no multi-line messages or embedded newlines.
+This function makes it easy for your program to report informative error
+messages about the failure of a library call.
+
+The value of @var{lz_errno} normally comes from a call to
+@samp{LZ_(de)compress_errno}.
+@end deftypefun
+
+
@node Data Format
@chapter Data Format
@cindex data format
@@ -528,7 +613,22 @@ Example 1: Normal compression (@var{member_size} > total output).
@sp 1
@noindent
-Example 2: Decompression.
+Example 2: Normal compression using LZ_compress_write_size.
+
+@example
+1) LZ_compress_open
+2) go to step 5 if LZ_compress_write_size returns 0
+3) LZ_compress_write
+4) if no more data to write, call LZ_compress_finish
+5) LZ_compress_read
+6) go back to step 2 until LZ_compress_finished returns 1
+7) LZ_compress_close
+@end example
+
+
+@sp 1
+@noindent
+Example 3: Decompression.
@example
1) LZ_decompress_open
@@ -544,19 +644,87 @@ Example 2: Decompression.
@sp 1
@noindent
-Example 3: Multimember compression (@var{member_size} < total output).
+Example 4: Decompression using LZ_decompress_write_size.
+
+@example
+1) LZ_decompress_open
+2) go to step 5 if LZ_decompress_write_size returns 0
+3) LZ_decompress_write
+4) if no more data to write, call LZ_decompress_finish
+5) LZ_decompress_read
+6) go back to step 2 until LZ_decompress_finished returns 1
+7) LZ_decompress_close
+@end example
+
+
+@sp 1
+@noindent
+Example 5: Multimember compression (@var{member_size} < total output).
+
+@example
+ 1) LZ_compress_open
+ 2) go to step 5 if LZ_compress_write_size returns 0
+ 3) LZ_compress_write
+ 4) if no more data to write, call LZ_compress_finish
+ 5) LZ_compress_read
+ 6) go back to step 2 until LZ_compress_member_finished returns 1
+ 7) go to step 10 if LZ_compress_finished() returns 1
+ 8) LZ_compress_restart_member
+ 9) go back to step 2
+10) LZ_compress_close
+@end example
+
+
+@sp 1
+@noindent
+Example 6: Multimember compression (user-restarted members).
@example
1) LZ_compress_open
2) LZ_compress_write
3) LZ_compress_read
- 4) go back to step 2 until LZ_compress_member_finished returns 1
- 5) LZ_compress_restart_member
- 6) go back to step 2 until all input data has been written
- 7) LZ_compress_finish
- 8) LZ_compress_read
- 9) go back to step 8 until LZ_compress_finished returns 1
-10) LZ_compress_close
+ 4) go back to step 2 until member termination is desired
+ 5) LZ_compress_finish
+ 6) LZ_compress_read
+ 7) go back to step 6 until LZ_compress_member_finished returns 1
+ 8) verify that LZ_compress_finished returns 1
+ 9) go to step 12 if all input data has been written
+10) LZ_compress_restart_member
+11) go back to step 2
+12) LZ_compress_close
+@end example
+
+
+@sp 1
+@noindent
+Example 7: Decompression with automatic removal of leading garbage.
+
+@example
+1) LZ_decompress_open
+2) LZ_decompress_sync_to_member
+3) go to step 6 if LZ_decompress_write_size returns 0
+4) LZ_decompress_write
+5) if no more data to write, call LZ_decompress_finish
+6) LZ_decompress_read
+7) go back to step 3 until LZ_decompress_finished returns 1
+8) LZ_decompress_close
+@end example
+
+
+@sp 1
+@noindent
+Example 8: Streamed decompression with automatic resynchronization to
+next member in case of data error.
+
+@example
+1) LZ_decompress_open
+2) go to step 5 if LZ_decompress_write_size returns 0
+3) LZ_decompress_write
+4) if no more data to write, call LZ_decompress_finish
+5) if LZ_decompress_read produces LZ_header_error or LZ_data_error,
+ call LZ_decompress_sync_to_member
+6) go back to step 2 until LZ_decompress_finished returns 1
+7) LZ_decompress_close
@end example